1. Field of the Invention
The invention relates to the field of printing systems, and in particular, to methods and systems for color conversions with toner/ink limitations.
2. Statement of the Problem
One concern in color printing regards the costs associated with toner/ink. While a certain amount of toner or ink is necessary for maintaining relatively high quality printing, toner and ink typically account for a substantial portion of the printing expenses. Traditionally, toner/ink has been conserved via a gray component replacement (GCR) process that includes under color removal (UCR) and under color addition (UCA) during color conversion. More specifically, GCR was the result of UCR followed by UCA.
In C, M, Y, K (cyan, magenta, yellow, and black) color printing, UCR is the process of eliminating certain amounts of cyan, magenta, and yellow that add to the dark neutral color, such as black. These colors are replaced with the less expensive black toner during the color separation process. However, black toner alone is not sufficiently dark and thus tends to produce relatively dull looking images (e.g., dark, less saturated, and hue shifted). UCA improves the relatively dull results of UCR by adding small portions of cyan, magenta, and yellow. However, the UCA process is empirical and fairly labor intensive due to the lack of a high fidelity model describing the nonlinear behavior of each toner. For example, UCA is commonly achieved by continually adding cyan, magenta, and/or yellow and printing until an esthetically pleasing image is produced.
As is evident, the GCR correction scheme based on the UCR and UCA is substantially error prone. Furthermore, the prior GCR is relatively incapable of dynamically adjusting to variations in print media that are known to cause variations in color conversions. Accordingly, there exists a need for a dynamic GCR that produces crisp bold images.